//file copy

#include <stdio.h>
#include <stdlib.h>
int main()
{
    int c;
    FILE *in, *out;
    in = fopen("file.in","r");
    out = fopen("file.out","w");

    while((c = fgetc(in)) != EOF)
        fputc(c,out);
    exit(0);
}

//I/O---
FILE *fopen(const char *filename,const char *mode);
FILE *fcloes(FILE *stream);
size_t fread(void *ptr. size_t size, size_t nitems, FILE *stream);
size_t fwrite(const void *ptr. size_t size, size_t nitems, FILE *stream);

int fflush(FILE *stream);
int fseek(FILE *stream, long offset,int whence);

int fgetc(FILE *stream);
int getc(FILE *stream);
int getchar();

int fputc(int c,FILE *stream);
int putc(int c,FILE *stream);
int putchar();

char *fgets(char *s, int n, FILE *stream);
char *gets(char *s);

/*
printf
fprintf
sprintf

scanf
fscanf
sscanf
*/

//文件流错误
#include <errno.h>

extern int errno;

int ferror(FILE *stream);
int feof(FILE *stream);
void clearerr(FILE *stream);

//文件流和文件描述符转换
int fileno(FILE *stream);
FILE *fdopen(int fildes, const char *mode);

int chmod(const char *path, mode_t mode);
chown
unlink
mkdir
rmdir
chdir//cd
getcwd//pwd


//目录操作
opendir
closedir
readdir
relldir
seekdir
